Door closer



Nov. 30, 1965 R. c. FLINT 3,220,047

DOOR CLOSER Filed Jan. lO, 1962 2 Sheets-Sheet 2 6.6 @o -5 f@ ff @1f W00f4 /03 l] Il' l /M l! f Aww W L93 gggigiggg "l I JNVENTOR.

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United States Patent Office 3,226,01113 Patented Nov. so, 1965 3,220,047DOOR CLOSER Russell C. Flint, Princeton, Ill., assiguor to Schlage LockCompany, San Francisco, Calif., a corporation of California Filed Jan.10, 1962, Ser. No. 165,330 14 Claims. (Cl. 16-62) The invention relatesto a door closer for controlling the movement of a door with respect toits door frame both in the opening direction and in the closingdirection. More particularly, the invention relates to a door closer ofthe spring and iluid type which has a piston head and a cooperatingcheck arrangement whereby the speed of the door operatively connected tothe door closer is checked or retarded just before it reaches its limitof movement in the door-opening direction and, furthermore, the speed ofthe door in the door-closing direction is controlled to assure properlatching without the door slamming against the door frame.

It is an object of the present invention to provide a door closer ofgenerally improved characteristics.

It is a further object of the present invention to provide a door closerthat will rapidly propel a door towards its closed position whilecontrolling the motion of the door throughout its closing and latchingoperation.

It is a further object of the present invention to provide a door closereffective to retard the movement of the door toward and near its extremeopen position; that is, to provide a back check.

It is a further object of the present invention to provide a simplifiedmeans of iluid control for an adjustable back check in a door closer.

It is a further object of the present invention to provide a door closerthat can be readily and economically manufactured.

The invention, both as to its organization and method of operation,taken with further objects and advantages thereof, will best beunderstood by reference to the following description taken in connectionwith the accompanying drawings, in which:

FIGURE l is a longitudinal, top cross-sectional View of a door closerconstructed in accordance with the present invention;

FIGURE 2 is a cross-sectional View of the door closer of FIGURE 1 takenalong line 2 2 of FIGURE l;

FIGURE 3 is an end view of the door closer of FIG- URE l taken alongline 3 3 of FIGURE l;

FIGURE 4 is a longitudinal, top cross-sectional view of the door closerof FIGURE l during the back check stage;

FIGURE 5 is a longitudinal, top cross-sectional view of the door closerof FIGURE 1 during the general speed stage;

FIGURE 6 is a fragmentary longitudinal, top crosssectional view of thedoor closer of FIGURE l during the latching speed stage; and

FIGURE 7 is a fragmentary longitudinal, top crosssectional view of thedoor closer of FIGURE 1 which has been adjusted for a quick releasestage, the door closer being illustrated during this stage.

Referring now to the drawings, and more particularly to FIGURES 1-3, thedoor closer of the present invention is indicated generally by referencenumeral 20. The door closer is operatively connected to a door suitablyhinged to a door frame (not shown). It is the function of the doorcloser 20 to control the speed and ease with which the door is openedand closed. Furthermore, the door closer 20 functions to assure that thedoor properly latches, without slamming, into the door frame. In thisconnection the door closer 20 permits the door to open at a relativelyrapid rate in response to a person pushing or pulling the door. This ishereinafter referred to as the initial door-opening stage. However, oncethe door has swung through a controllable predetermined arc, such asabout 70, the door enters the stage hereinafter referred to as the backcheck stage; that is, the door closer 20 is adapted to increase theamount of force necessary to open the door past this predetermined arcand to reduce the opening speed of the door during this back checkstage.

Once the door has completed its opening operation, the door closer 20allows the door to close at a rapid or slow speed, as desired, until ithas returned relatively close to the door frame. This stage ishereinafter referred to as the general speed stage. After completingthis stage, the door goes through the nal stage of its closing operationin which it latches in the door frame. During this final stage the doorcloser 20 will assure that the door has suicient speed to properlylatch, yet not enough speed to bang or slam into the door frame. Thus ifthe door during the general speed stage has been closing at a rapidrate, the door closer 20, in effect, brakes the speed of the door toassure that it will not bang or slam into the door frame and yetproperly latch, which is referred to hereinafter as the latching speedstage. On the other hand, if the door closer 20 has been set so thatduring the general speed stage the door is closing very slowly, then thedoor closer 20 allows the door to speed up sufficiently to assure properlatching, which is hereinafter referred to as the quick release stage.

To these ends the door closer 20 includes a main body 22, preferably ofcast metal, contoured with grooves to provide anges 24 and 26 designedfor sliding engagement endwise with the runs of a mounting bracket, suchas shown in the U.S. Patent No. 2,723,416. The body 22 is installed bysliding it endwise into the bracket so that the weight of the doorcloser 20 is readily borne by the door or door frame to which themounting bracket is attached. The door closer 20 is readily installed inthis .manner in either its upright or inverted position, so that it issuitable for use on a right-hand door, a left-hand door or on the doorframe associated with such a righthand or left-hand door. Furthermore,the door closer 20 may be arranged or mounted in a vertical directionfor use in conjunction with sliding doors.

The main body 22 is provided with a transverse bore 28. At its oppositeends, the bore 28 is formed with threaded terminals 30 and 32 into whichjournal sleeves 34 and 36, respectively, are tightly screwed. Thesleeves 34 and 36 carry anti-friction bushings 38 and 40 within whichthe journal portions 42 and 44 of a driving spindle 46 are mounted.Symmetrically disposed between the ends of the spindle 46, andpreferably formed integrally therewith, is a pinion 50 having a full ora partial set of gear teeth' of a standard contour. Suitable gaskets andpacking rings (not shown) are interposed to prevent leakage around thejournal portions 42 and 44 of the driving spindle 46 and the journalsleeves 34 and 36. The journal portions 42 and 44 of the spindle 46project beyond the sleeves 34 and 36. The spindle 46 is driven from oneend only at a time although either end may be utilized alternatively.The journal ends of the spindle 46 are nished with serrations 48engageable with mating serrations in a hub of a driving arm, which ispart of the cooperating linkage (not shown) between the door closer 20and the door. The end of the spindle 46 not in use at any one time maybe closed by a cap (not shown).

In any of these several possible mountings discussed hereinbefore, whenthe door is opened the cooper-ating linkage between the door and thedoor closer 20 produces a rota-tion of the spindle 46 within and withrespect to the :main body 22. This relative rotation of the spindle 46is utilized to effect the desired closing and checking functions to bedescribed in more detail hereinafter.

Within the main body y22 and partially intersecting the transverse bore28 is a longitudinal, circular cylindrical bore or piston chamber 52.The piston chamber `52 extends longitudinally through the entire mainbody 22. The opposite ends of the piston chamber 52 are closed byidentical plugs 54 and' 56 threaded into position and conning suitablesealing rings (not shown) to prevent leakage. Operatively positionedwithin the Piston charnber 52 is a piston 58 having a piston head 60Vand an annular piston skirt 62, one end of which is attached to thepiston head 60. The annular piston skirt 62 forms a 'cavity 64 openingat the free end of the piston skirt 62 to the piston chamber 52.Adjacent the free end of the piston skirt 62 is an annular ridge 63which, like the piston head 60, is in uid tight engagement with the wallof the piston chamber 52. The piston skirt 62, the piston head 60, theridge 63 and the body 22 form an annular zone 65 within the pistonchamber 52.

Along one side of the piston skirt 62 Ithere is provided a plurality ofgear teeth 66 constituting a rack in engagement with the pinion lSti, sothat upon rotation of the pinion 50, the rack and the piston 58 arecorrespondingly reciprocated. Despite the motion of the piston `58, theannular zone 65 always communicates with the bore 28 so that the bore 28and the annular zone 65 are isolated from the ends of the piston chamber52, except for the communication therebetween alorded by the piston head60.

The piston head i60 has a longitudinally extending piston headpassageway 162, one end of which communitcates with the piston chamber`52 and the other end communicates with the cavity 64. Opposing one-wayball valves or check valves 98 and 100 are positioned within thepassageway :102. The check valve `98 prevents flu-id from entering thepassageway 102 from the cavity 64, but allows fluid to flow into thecavity 64 from the passageway 102. Likewise, the check valve 100prevents fluid from entering the passageway 102 from the piston chamber52, but allows iluid to ow into the piston chamber y52 from thepassageway 102. The piston head `60 also contains a radially extendingpassageway 104 which communicates with the piston head passageway 102between the check valves 98 and 100. One end of the passageway 104communicates with the annular zone 65 and the bore 28. The other end ofthe passageway 104 is blocked oit by the main body 22 when the pistonhead '60 is lin the piston chamber r52.

Normally the piston 58 is urged toward one extreme position 4by ahelically coiled compression spring 68. The spring 68 bears at one endon the plug 54, passes through the cavity 64 and at the other end bearsagainst the piston head 60. The .spring 68 has sufficient strength tourge vthe door toward the closed position against all ordinary forceswhich tend to oppose such closing movement. However, when the door isopened, the cooperating linkage (not shown) between the door and thedoor closer 20 is such that the pinion 50 is rotated in a clockwisedirection and the piston 58 is moved `toward the right (when viewingyFIGURE l), the spring 68 being compressed. When the door is released inthe open position, the spring 68 elects door closing and is suicientlyforceful to move `the door -to a closed latched position in the doorframe.

In order to control the movement of the door in both its opening andclosing directions, a body of hydraulic fluid, such as oil or an oilsubstitute, is ydisposed within the piston chamber `52. The oil lieswithin the variable chambers at opposite ends of the piston chamber 52partly bounded by the interposed piston 58. Only through the valvingarrangement to be described may the fluid flow directly from the pistonchamber 52 into the bore 28.

`Communicating with the far 4right of `the piston chamber 52 is apassageway 70 leading to a by-pass passageway 72 communicating with thebore 28. Also communicating with the piston chamber 52 and the by-passpassageway 72 is a passageway 74. The passageway 74 communicates withthe piston chamber 512 at a point spaced longitudinally from the pointat which the passageway 70 communicates with the piston chamber 52.Likewise, the passageway 74 communicates `with the bypass passageway 72at a point spaced longitudinally from the point at which the passageway7 0 communicates with the by-pass passageway 72. 4Sealing off one end ofthe by-pass passageway l72 is an adjustable needle valve or fthe like`76 threadly engaging the main body 22. The needle valve 76 forms withthe by-pass passageway 72 a restricted variable orifice 78 locatedbetween the points where passageways 74 and 70 communicate with thebypass passageway 72. The needle valve 76 may be rotated to increase ordecrease the size of the orice 78 and thereby adjust the opening of thedoor in a manner more apparent hereinafter.

It will be understood that many types of valves may be employed for theadjustable orice 78 in the bypass passageway 72. The particular valveutilized forms no part of the present invention, its selection being amatter within the skill of one in the art.

Communicating with the far left end of the piston chamber `52 is apassageway 80 leading to a by-pass passageway 82 communicating with thebore 28. Also communicating with the piston chamber 52 and the by-passpassageway 82 is a passageway 84. The passageway 84 communicates withthe piston chamber =52 at a point spaced longitudinally from the pointat which the passageway communicates with the piston chamber `52.Llkewise, the passageway 84 communicates with the bypass passageway 82at a point spaced longitudinally from the point at which the passageway801 communicates with the by-pass passageway `82.

A sleeve member 86 is positioned within the by-pass passageway 82 andhas a radial hole 88 communicating with the passageway 80 and a radial'hole 90 communicating with the passageway 84. Sealing off one end ofthe by-pass passageway 82 is an adjustable dual needle valve or the like92 threadedly engaging the main body 22. The needle valve 92 has aplurality of longitudinal slots 94, one of which communicates with theradial hole 88 to form, with the sleeve 86, a variable orifice in theby-pass passageway 82 lbetween the passageway 80 and an annular zonecommunicating with the passageway 84. In addition, the needle valve 92forms with the sleeve 86 -a restricted, variable orifice 96 positionedbetween where the passageway 84 communicates with the by-pass passageway82 and where the by-pass passageway 82 communicates with the bore 28.Both orices may be independently increased or decreased in size byproper rotation of the needle valve 92. In the embodiment illustratedthe orilice formed by the slot 94 has been adjusted to be smaller thanthe oriiice 96. It will be understood that any valve means may beemployed for these restricted orifices and that the particular valvemeans employed for these orices is not, per se, part ofthe presentinvention.

The door closer 20 is illustrated in FIGURES 1-3 at rest; that is, whenthe door is closed. When the door is opened the spindle 46 and pinion50` are rotated in a clockwise direction when viewing FIGURE l, therebytranslating the piston 58 toward the right against the force exerted bythe spring 68. During the initial door-opening stage7 which ends whenthe ridge 63 of the piston skirt 62 closes oit the passageway 74, thecheck valve 98 will be forced into its closed position and fluid will beforced from the piston chamber 52 into the passageway 74, the by-passpassageway 72 and the bore 28. From the bore 28 the fluid flows into thelannular zone 65 between the housing 22 and the piston skirt 62 andthere enters the radial passageway 104. The iluid passes through thepiston head passageway 102 and the check valve 100 into the pistonchamber 52 on the trailing end of the piston 58. The iiuid forced fromthe piston chamber 52 takes, of course, the path of least resistancethrough the valving arrangement in the body 22. lFor this reason littlefluid will pass through the passageway 70 and orifice 78 to the other,or trailing, end of piston 58, since the orifice 78 places a restrictionupon the `flow path which does not exist if the fluid fiows through thepassageway 74 in the manner described.

The initial door-opening stage continues until the ridge 63 of thepiston skirt 62 has closed ofi the passageway 74, as illustrated inFIGURE 4. At this point the door and door closer 20 enter the back checkstage. FIGURE 4 illustrates the position of the piston 58 during theback check stage and the .arrows in FIGURE 4 indicate the iiow path ofthe iiuid during this stage. Since the passageway 74 has been blockedoff by the ridge 63, the fluid must pass through the passageway 70, theby-pass passageway 72 and the restricted oriiice '78 into the bore 28.The fluid enters the annular Zone 65 and -flows through the passageways104 and 102 and the check valve 100 to the trailing end of the piston58. During this back check stage, the liuid flowing to the trailing endof the pist-on 58 must pass through the restricted orifice 78, which hasthe effect of reducing the speed of the opening door. |Furthermore,during the back check stage it will require more pressure than duringthe initial door opening stage to further open the door.

When the door is released in the open position it will begin its closingoperation -by virtue of the spring 68 acting against the piston head 60and urging the piston 58 toward the left. Movement of the piston 58toward the left will cause rotation of the pinion 50 and the spindle 46thereby causing the door to close by virtue of the cooperating armlinkage (not shown) between the door closer 20 and the door frame.FIGURE 5 illustrates the general speed stage; that is, the stage inwhich the piston 58 moves toward the left 'but prior to its blocking ofithe passageway 84. The arrows in FIGURE 5 indicate the main flow path ofthe iiuid during this stage. y

During the general speed stage, the check valve 100 closes and iiuidwill be forced through the passageway 84, the annular zone 95 betweenthe sleeve 86 and the needle valve 92 and the restricted orifice 96,into the by-pass passageway 82. The fluid then flows into the bore 28around the pinion 50 into the annular zone 65 around the piston skirt`62 where it enters the passageway 104 in the piston head 60. The fluidleaves the piston head 60 through the passageway 102 and the check valve98 and enters the piston cavity 64 on the trailing end of the pistonhead 60. Some iiuid may iiow from the cylindrical bore 28 through theby-pass passageway 72 to passageway 74 and there enter the pistonchamber 52 on the trailing end of the piston 58, however, this pat-h isgenerally of greater resistance than the main flow path describedherei'nbefore and thus will not carry the bulk of the iiuid beingbypassed around the piston head 60.

When the piston 4head 60 has blocked off the passageway 84, the doorenters the latching speed stage at which time the door is relativelyclose to the door frame. This is the stage in which the speed of t-hedoor is substantially reduced to prevent the door from slamming into thedoor frame. FIGURE 6 illustrates the position of the piston 58 and the`arrows in this figure indicate the ow of fluid in the door closer 20during the latching speed stage.

During the latching speed stage the piston 58 moves toward the left andthe check valve 100 is thereby closed. Fluid is forced from the pistonchamber 52 through the passageway 80, the restricted orifice formed bythe slot 94, the annular zone 95, the restricted orifice 96 and into theby-pass pasageway 82. From the by-pass passageway 82 the fiuid passesthrough the bore 28 and into the annular zone 65 around the piston skirt62. The fluid passes through the radially extending passageway 104 intothe piston head pasageway 102 and through the open check valve 98 intothe cavity 64 formed by the piston skirt 62. There will be some iiow ofliu-id through the by-pass passageway 72 and the passageway 74 for thereasons discussed hereinbefore with respect to the general speed stage.It will be understood that since the fluid displaced from the pistonchamber 52 must, during the latching speed stage, flow through theorifice formed by the slots 94, which is more restricted in thisinstance than orifice 96, that the iiow of fluid is decreasedsubstantially, thereby substantially reducing the speed of the closingdoor to insure latch-ing without slamming into the door frame.

The latching speed stage continues when the piston head 60 moves pastthe passageway 84 and terminates when the door is securely latched inthe door frame.

The door closer 20 may be adjusted to achieve, among other things, aslow closing speed during the general speed stage such that it isnecessary to increase the speed of the door just before it reaches thedoor frame to assure proper latching, i.e., a quick release stage. Thismodification is achieved by adjusting needle Vlalve 92 to make theorifice 96 smaller than the orifice formed by the slots 94. This has noeffect on the initial door-opening stage and back check stage discussedhereinbefore. Now, however, during the genenal speed stage, though theow path of the fluid is not altered, the orice `96 only permits the doorto close slowly. In this instance, the general speed stage continuesuntil the piston head 60 has moved past the passageway 84 as illustratedin FIGURE 7. Then the quick release stage begins, the flow of fiuidduring this quick release stage being illustrated in FIGURE 7. Fluidforced from the piston chamber 52 passes through the passageway 80 andthe restricted orifice formed by slot 94 into the annular zone 95. Fromthe annular zone 95 the fluid passes through the hole into thepassageway 84 where it flows into the annular zone 65 around the pistonchamber 52. The iiuid passes through the piston head 60 via thepassageway 104, the piston head passageway 102 and the check valve 98,to the cavity 64 :at the trail-ing end of the piston head 60. It will beunderstood that in this embodiment since the fluid need only fiowthrough the orifice formed by the slot 94 during the quick release stagethe speed of the door will increase as compared to its speed during thegeneral speed stage. In this manner, the door speeds up sufficientlyduring the quick release stage to assure proper latching. i While theembodiments described herein are at present considered to be preferred,it is understood that Various modifications and improvements may be madeand it is intended to cover in the appended claims all suchmodifications and improvements as fall within the true spirit and scopeof the invention.

What is desired to be claimed and secured by Letters Patent of theUnited States is:

1. In a door closer including a body having a cylindrical pistonchamber, a piston in said piston chamber, spring means for urging saidpiston along said piston chamber in one direction, said piston having apiston head with two sides, said piston head forming first and secondchambers in said piston chamber, said piston including means forming athird chamber 'in said piston chamber, said piston head having alongitudinal passageway extending from one of said sides to the other ofsaid sides, first and second one-way valves in said passageway inopposing relationship, said piston having a second passageway thereinhaving one end communicating with said third chamber and another endcommunicating with said longitudinal passageway between said first andsecond valves, and a valving arrangement within said body whereby fluidforced from said piston chamber by one side of said piston head passesto said piston chamber on the other side of the piston head when thepiston head is moving in said piston chamber in either direction.

2. In the door closer of claim 1 wherein said uid forced from saidpiston chamber flows to said other side of said piston head through saidlongitudinal passageway in said piston head.

3. In a door closer including a body having a cylindrical pistonchamber, a piston in said piston chamber, a spring means for urging saidpiston along said piston chamber in one direction, said piston having apiston head with two sides, said piston head forming first and secondchambers in said piston chamber, said piston including means forming athird chamber in said piston chamber, said piston head having alongitudinal passageway extending from one of said sides to the other ofsaid sides, first and second one-way valves in said passageway inopposing relationship, said piston having a second passageway thereinhaving one end communicating with said third chamber and another endcommunicating with said longitudinal passageway between said first andsecond valves, and a valving arrangement within said body whereby fiuidforced from said piston chamber by one side of said piston head passesto said piston chamber on the other` side of said piston head when thepiston is moving in said piston chamber in either direction, saidvalving arrangement including first and second passageways in said bodycommunicating with one end of said piston chamber, said first and secondpassageways being spaced from one another along the longitudinal axis ofthe said piston chamber, said first and second passageways communicatingwith a by-pass passageway, said by-pass passageway communicating withsaid third chamber, a valve within said by-pass passageway positionedbetween where said first and second passageways communicate with saidbypass passageway, whereby when one side of said piston is moved in adirection opposing the force of said spring fluid displaced from saidpiston chamber passes through said first passageway, said by-passpassageway and said longitudinal passageway to the other side of saidpiston head until said first passageway is closed by said piston,wherein fiuid displaced from said piston chamber passes through saidsecond passageway, said valve, said by-pass passageway and saidlongitudinal passageway to the other side of said piston head.

4. In the door closer of claim 3 wherein third and fourth passageways insaid body communicate with the other end of said piston chamber, saidthird and fourth passageways being spaced from one another along thelongitudinal axis of said piston chamber, said third and fourthpassageways communicating with a second by-pass passageway, said secondby-pass passageway communicating with said third chamber, a first valvein said second by-pass passageway between where said third and fourthpassageways communicate with said second bypass passageway, and a secondvalve in said second bypass passageway between where said fourthpassageway communicates with said second by-pass passageway and saidsecond by-pass passageway communicates with said piston chamber.

5. In a door closer including a body having a cylindrical pistonchamber, a piston in said piston chamber, said piston having a pistonhead and an annular piston skirt, one end of said piston skirt beingconnected to said piston head, the other end of said piston skirt havinga ridge which is in substantially fluid tight engagement with saidpiston chamber, spring means for urging said piston along said pistonchamber in one direction, said piston head having a longitudinallyextending passageway therethrough, said passageway having first andsecond one-way valves in opposing relationship, a second passageway insaid piston head communicating with said longitudinal passageway in saidpiston head between said first and second one-way valves, said secondpassageway communicating with said piston chamber on the outside of saidpiston skirt, and a valving arrangement within said body whereby fiuidmay pass from one side of said piston head to the other side of saidpiston head through said passageways in said piston head when saidpiston head is moving in said piston chamber.

6. In a door closer including a body having a cylindrical pistonchamber, a piston in said piston chamber, said piston having a pistonhead and an annular piston skirt, oneend of said piston skirt beingconnected to said piston head, the other end of said piston skirt havinga ridge which is in substantially fluid tight engagement with saidpiston chamber, spring means for urging said piston along said pistonchamber in one direction, said piston head having a longitudinallyextending passageway therethrough, said passageway having first andsecond one-way valves in opposing relationship, a second passageway insaid piston head communicating with said longitudinal passageway in saidpiston head between said first and second one-way valves, said secondpassageway communicating with said piston chamber on the outside of saidpiston skirt, and a valving arrangement within said body whereby iiuidmay pass from one side of said piston head to the other side of saidpiston head through said passageways in said piston head when saidpiston head is moving in said piston chamber, said valving arrangementincluding first and second passageways in said body communicating withone end of said piston chamber, said first and second passageways beingspaced from one another along the longitudinal axis of said pistonchamber, said first and second passageways communicating with a iirstby-pass passageway, said first by-pass passageway communicating withsaid piston chamber between said piston head and said ridge on saidpiston skirt, a first valve in said first by-pass passageway betweenwhere said first and second passageways communicate with said firstby-pass passageway.

7. In the door closer of claim 6 wherein third and fourth passageways insaid body communicate with the other end of said piston chamber, saidthird and fourth passageways being spaced from one another along thelongitudinal axis of said piston chamber, said third and fourthpassageways communicating with a second by-pass passageway, said secondby-pass passageway communicating with said piston chamber between saidpiston head and said ridge on said piston skirt, first and second valvein said second by-pass passageway, said first valve being positionedbetween where said third and fourth passageways communicate with saidsecond by-pass passageway, and said second valve being positionedbetween where said fourth passageway communicates with said secondby-pass passageway and said second by-pass passageway communicates withsaid piston chamber.

8. A door closer comprising a body having a cylindrical piston chamber,a piston in said piston chamber, said piston having a piston head and anannular piston skirt, one end of said piston skirt being connected tosaid piston head, the other end of said piston skirt having a ridgewhich is in substantially fluid tight engagement with said pistonchamber, said piston skirt having a gear rack, a transverse bore in saidbody communicating with said piston chamber between said piston head andsaid ridge of said piston skirt, a pinion shaft journalled in said bore,a gear on said pinion shaft meshing with said rack, spring means forurging said piston along said piston chamber in one direction, saidpiston head having a longitudinally extending passageway therethrough,said passageway having first and second one-way valves in opposingrelationship, a second passageway in said piston head communicating withsaid longitudinally passageway in said piston head between said firstand second one-way valves, said second passageway communicating withsaid piston chamber on the outside of said piston skirt, and a valvingarrangement within said body whereby fluid may pass from one side ofsaid piston head to the other side of said piston head through saidpassageways in said piston head when said piston head is moving in saidpiston chamber.

9. A door closer comprising a body having a cylindrical piston chamber,a piston in said piston chamber, said piston having a piston head and anannular piston skirt, one end of said piston skirt being connected tosaid piston head, the other end of said piston skirt having a ridgewhich is in substantially fiuid tight engagement with said pistonchamber, said piston skirt having a gear rack, a transverse bore in saidbody communicating with said piston chamber between said piston head andsaid ridge of said piston skirt, a pinion shaft journalled in said bore,a gear on said pinion shaft meshing with said rack, spring means forurging said piston along said piston chamber in one direction, saidpiston head having a longitudinally extending passageway therethrough,said passageway having first and second one-way valves in opposingrelationship, a second passageway in said piston head communicating withsaid longitudinal passageway in said piston head between said first andsecond one-way valves, said second passageway communicating with saidpiston chamber on the outside of said piston skirt, and a valvingarrangement within said body whereby fluid may pass from one side ofsaid piston head to the other side of said piston head through saidpassageway in said piston head when said piston head is moving in saidpiston chamber, said valving arrangement including first and secondpassageways in said body communicating with one end of said pistonchamber, said first and second passageways being spaced from one anotheralong the longitudinally axis of said piston chamber, said first andsecond passageways communicating with a first by-pass passageway, saidfirst by-pass passageway communicating with said bore, a first valve insaid first by-pass passageway between where said first and secondpassageways communicate with said first by-pass passageway.

10. The door closer of claim 9 wherein third and fourth passageways insaid body communicate with the other end of said piston chamber, saidthird and fourth passageways being spaced from one another along thelongitudinal axis of said piston chamber, said third and fourthpassageways communicating with a second by-pass passageway, said secondby-pass passageway communicating with said bore, first and second valvein said second by-pass passageway, said first valve being positionedbetween where said third and fourth passageways communicate with saidsecond by-pass passageway, and said second valve between where saidfourth passageway communicates with said second by-pass passageway andsaid second by-pass passageway communicates with said bore.

11. In a door closer including a body having a cylindrical pistonchamber, a piston in said piston chamber, spring means for urging saidpiston in one direction in said piston chamber, said piston having apiston head forming first and second chambers in said piston chamber,said piston head having a first passageway communicating with said firstand second chambers, first and second oneway valves in opposingrelationship in said first passageway, said piston including meansforming a third charnber in said piston chamber, said piston having asecond passageway therein having one end communicating with said thirdchamber and another end communicating with said first passageway betweensaid first and second oneway valves, said third chamber alsocommunicating with said first and second chambers through a valvearrangement in said body member.

12. In the door closer of claim 11 wherein said means forming a thirdchamber in said piston chamber is a piston skirt having one end attachedto said piston head and another end having a ridge which is insubstantially fluid tight engagement with said piston chamber, saidvalving arrangement including third and fourth passageways in said bodycommunicating with said second chamber, said third and fourthpassageways being spaced from one another along the longitudinal axis ofsaid second chamber, said third and fourth passageways communicatingwith a by-pass passageway, said by-pass passageway communicating withsaid first chamber and said third chamber, a first valve means withinsaid by-pass passageway positioned between where said third and fourthpassageways communicate with said by-pass passageway.

13. In the door closer of claim 12 wherein fifth and sixth passagewaysin said body communicate with said first chamber, said fifth and sixthpassageways being spaced from one another along the longitudinal axis ofsaid first chamber, said fifth and sixth passageways communicating witha second by-pass passageway, said second bypass passageway communicatingwith said third chamber, a second valve means in said second by-passpassageway between where said fifth and sixth passageways communicatewith said second by-pass passageway, and a second valve means in saidsecond by-pass passageway between where said sixth passagewaycommunicates with said second by-pass passageway and said second by-passpassageway communicates with said third chamber.

14. In the door closer of claim 11 wherein movement of said piston inone direction causes fluid to be transferred from said second pistonchamber to said first chamber through said valving arrangement, saidthird chamber and said first passageway, and movement of said piston insaid other direction causes fluid to be displaced from said firstchamber to said second chamber through said valving arrangement, saidthird chamber and said first passageway.

References Cited by the Examiner UNITED STATES PATENTS 1,521,682 1/1925Gunn 18S- 88.8 1,786,782 12/1930 Shonnard 16-62 1,863,296 6/1932 Chryst18S-88.7 2,087,350 7/1937 McCann l88-88.7 2,716,995 9/1955 Baugh et al137-506 2,790,991 5/ 1957 Schlage 16-62 DONLEY I. STOCKING, PrimaryExaminer,

1. IN A DOOR CLOSER INCLUDING A BODY HAVING A CYLINDRICAL PISTONCHAMBER, A PISTON IN SAID PISTON CHAMBER, SPRING MEANS FOR URGING SAIDPISTON ALONG SAID PISTON CHAMBER IN ONE DIRECTION, SAID PISTON HAVING APISTON HEAD WITH TWO SIDES, SAID PISTON HEAD FORMING FIRST AND SECONDCHAMBERS IN SAID PISTON CHAMBER, SAID PISTON INCLUDING MEANS FORMING ATHIRD CHAMBER IN SAID PISTON CHAMBER, SAID PISTON HEAD HAVING ALONGITUDINAL PASSAGEWAY EXTENDING FROM ONE OF SAID SIDES TO THE OTHER OFSAID SIDES, FIRST AND SECOND ONE-WAY VALVES IN SAID PASSAGEWAY INOPPOSING RELATIONSHIP, SAID PISTON HAVING A